This invention relates generally to roadway resurfacing apparatus, and more particularly to a new and improved asphalt concrete conveyor arrangement for such road resurfacing apparatus. This invention deals with substantial improvements in handling of asphalt concrete mixtures during road repaving operations.
Road resurfacing apparatus, in general, is set forth in my earlier filed U.S. Pat. No. 3,361,042 which discloses means for quickly and inexpensively resurfacing roadways made of asphalt concrete material and the like. The apparatus may be from 8 to 12 feet wide and from forty to fifty feet long and move along the roadway at a slow rate of speed so that during a single continuous pass over the pavement, the old road surface in front of the machine is excavated and converted into a refinished road surface at the rear of the machine. During the conversion of an old road to a new road, new asphalt concrete mixtures may be added to either compensate for material missing as a result of potholes in the road or to provide a road surface which is thicker than the old road surface. A distinct advantage of repaving apparatus of the type disclosed in the above-mentioned patent is that the finished repaved strip of highway is substantially immediately available for traffic after it is completed.
Briefly, the road repaving apparatus first heats the road in a non-oxidizing environment consisting substantially of radiant heat so that the heat penetrates through the asphalt concrete pavement to a depth of approximately one inch or so. This is substantially immediately followed by a scarifying operation which deeply excavates the heated asphalt material to disarrange the surface to a depth of at least the depth of heat penetration, and generally to a depth of 1 or 2 inches more. Then the loosened material is piled for maximum surface exposure so that it can be further heated by either the same or a second following heating apparatus. If it is found necessary to add a given amount of conventional tack coat material or the like to help weld the total conglomeration of mixture to the substrate from which the heated material was removed, such coating is then applied. Also, this may be followed by adding additional asphalt concrete material as required. The asphalt concrete material is received from a conveyor which originates at the front of the machine where the material is loaded into a hopper by trucks or the like. The asphalt concrete material is then conveyed along the length of the machine above and past the heating and scarifying equipment where it is delivered to a dispensing area for combining the new material with the excavated material.
Heretofore, suggested means for conveying of the additional asphalt concrete material included a continuous conveyor having a material receiving platform engaged by a plurality of spaced apart scraper bars or flights secured between parallel endless chains for moving the material therealong. A trough located beneath the platform was adapted to catch and receive material which might inadvertently fall en route to the dispensing station. The material falling into the trough would be scraped therefrom by the return flights of the conveyor and periodically the end of the conveying apparatus, where the return flights wrap around the tail shaft, would have to be cleaned of excess asphalt concrete material. Furthermore, because of the nature of the heretofore suggested conveying apparatus, the total height or thickness of the layer of conveyed material is limited, which in turn limits the amount of asphalt concrete material being delivered. If a desired volume of material was to be delivered for unit time, the speed of the conveyor had to be increased. By requiring the conveyor flights to travel at higher speeds, the abrasive nature of the asphalt concrete material would cause the conveyor to wear at a faster rate.